Michel Eug癡ne Chevreul (August 31, 1786 - April 9, 1889) was a French chemist whose work with fatty acids led to early applications in the fields of art and science. He is credited with the discovery of margaric acid and designing an early form of soap made from animal fats and salt. He discovered the composition of stearin, a white substance found in the solid parts of most animal and vegetable fats, and olein, the liquid part of any fat, and to isolate stearic and oleic acids, the names of which he invented. This work led to important improvements in the processes of candle-manufacture. Chevreul was against charlatanism in every form, and a complete sceptic as to the "scientific" psychical research or spiritualism. Chevreul was also influential in the world of art. He determined that perceived color was influenced by other surrounding colors leading him to create a classification of colors and chromatic diagram. This led to a concept known as simultaneous contrast. He lived to 102 and was a pioneer in the field of gerontology. His is one of the 72 names inscribed on the Eiffel Tower.